目的: 探索在2022年医保目录简易续约背景下是否存在一类特殊现象,即部分药品会不断触发连续降价条件以致最终退出医保目录。方法: 本文通过构建需求价格弹性模型,结合医保目录谈判和续约规则进行数值模拟,对多轮简易续约情况进行讨论,以验证简易续约规则是否影响药品可持续供应。最后,本文对可行性方案的适用条件进行数理分析。结果: 在2022年简易续约规则下,市场上确实存在一类药品,当其首次医保谈判药品降价幅度和其弧弹性满足一定条件时,会陷入无限降价的困境。该现象可能是由于企业错估药品需求或是进入医保目录后药品销量飙升,量价线性关系被打破。减少续约次数和重新谈判能够降低此类现象发生的可能性。结论: 2023年简易续约规则一定程度上避免了此类现象的发生,后续政策可将阶梯型降价标准改为连续型。

Objective: The paper explores whether there is a special phenomenon under the background of the 2022 National Reimbursement Drug List (NRDL)'s simplified renewal rule, wherein some drugs may continuously trigger successive price reductions to the extent of eventually exiting the NRDL. Methods: This paper constructs a demand-price elasticity model, combined with numerical simulations of NRDL negotiation and renewal rules, to discuss the case of multiple rounds of simplified renewals and validate whether the simplified renewal rules affect the sustainable supply of drugs. Finally, this paper conducts a mathematical analysis of the applicable conditions for feasible solutions. Results: Under the 2022 simplified renewal rules, there is a class of drugs in the market that, when the initial price reduction during NRDL negotiation and its elasticity meet certain conditions, will fall into the dilemma of infinite price reduction. This phenomenon may be due to companies' misjudgment of drug demand or a surge in drug sales after entering the NRDL, breaking the linear relationship between quantity and price. Reducing the number of renewals and renegotiations can reduce the likelihood of such occurrences. Conclusion: The 2023 simplified renewal rules have, to some extent, avoided the occurrence of such phenomena. This paper suggests that subsequent policy modifications can change the stepped price reduction standard to a continuous one.